London: Defending champion Serena Williams broke down in tears as she made an emotional Wimbledon return while Roger Federer, Novak Djokovic and Maria Sharapova barely broke sweat.
Four-time winner Williams, watched by US pop superstar Diana Ross and England`s Ashes-winning cricketers in the Royal Box, battled past Frenchwoman Aravane Rezai 6-3, 3-6, 6-1 in what was only her third match in 11 months.
"I usually don`t cry. It`s been so hard, I never dreamt I`d be here," said Williams.
The great American was sidelined for 11 months after her 2010 Wimbledon triumph.
She suffered a foot injury caused by stepping on broken glass at a German restaurant before needing emergency surgery to remove blood clots on her lungs, an incident Williams described as being on her death bed.
"I just wanted to win at least one match here and since I`m not playing doubles it was a really big win for me.”
"To be able to come back at Wimbledon is pretty awesome, I didn`t expect to play or do anything," added seventh-seed Williams, who next tackles Romania`s Simona Halep.
Six-time men`s champion Federer, chasing Pete Sampras`s record of seven titles, cruised to a 7-6 (7/2), 6-4, 6-2 win over Mikhail Kukushkin of Kazakhstan.
Third-seeded Federer, who next faces France`s Adrian Mannarino, suffered a shock quarter-final exit against Tomas Berdych last year, but never looked in trouble against tournament debutant Kuskushkin.
The Swiss star fired down 12 aces and unleashed 53 winners in his quickfire Centre Court win.
"It was very windy and the conditions were tough," said Federer, the holder of a record 16 Grand Slam titles.
"It`s always nerve-wracking playing your first match on Centre Court because you don`t get the chance to practice at the start of the tournament. But it was a matter of playing solid."
Second seed Djokovic, playing for the first time since Federer ended his 43-match winning run in the French Open semi-finals, was equally untroubled needing just 80 minutes to defeat France`s Jeremy Chardy 6-4, 6-1, 6-1.
"When this streak ended in Paris, it was kind of a relief because it`s been a very successful five or six months for me, but very long as well and exhausting," said Australian Open champion Djokovic.
Fifth seed Maria Sharapova, the 2004 champion, powered past Russian Anna Chakvetadze 6-2, 6-1 and next faces either British wildcard Laura Robson or Germany`s Angelique Kerber.
Sharapova believes she can win another All England Club title.
"It would be a wonderful achievement. I`m really happy to be playing something that I really love," she said.
China`s French Open champion Li Na also won her opener with a comfortable 6-3, 6-3 win over Russia`s Alla Kudryavtseva.
Third seed Li, the first Asian to win a Grand Slam singles title in Paris, next faces either Germany`s Sabine Lisicki or Anastasija Sevastova for a place in the last 32.
Three-time finalist Andy Roddick eased into the second round with a 6-4, 7-6 (8/6), 6-3 over German qualifier Andreas Beck, while former US Open winner Juan Martin del Potro beat Flavio Cipolla 6-1, 6-4, 6-3.
John Isner ensured there would be no repeat of his historic Wimbledon marathon against France`s Nicolas Mahut as the American won their first round rematch 7-6 (7/4), 6-2, 7-6 (8/6).
Isner and Mahut had played the longest match in tennis history -- lasting 11 hours and five minutes and spread over three days -- when they met at the same stage at Wimbledon 12 months ago.
But American Isner, who won that record-breaking epic 70-68 in the fifth set, enjoyed a much less draining victory this time as he saw off Mahut in just over two hours.
"I definitely wanted to finish it here because otherwise everybody would be talking about a second day," said Isner.
Women`s world number one Caroline Wozniacki raced into the second round as she routed Spain`s Arantxa Parra Santonja 6-2, 6-1, taking just 59 minutes to demolish the world number 105.
Australian 10th seed Samantha Stosur, last year`s French Open runner-up, crashed out, losing 6-3, 6-4 to Hungary`s Melinda Czink.
Former world number one Jelena Jankovic, the 15th seed, went out to Spanish left-hander Maria Jose Martinez 5-7, 6-4, 6-3.
Fourth seeded Belarusian Victoria Azarenka went through when Magdelana Rybarikova of Slovakia retired with a knee injury in the second set.
Czech eighth seed Petra Kvitova, a semi-finalist in 2010, stormed past American qualifier Alexa Glatch 6-2, 6-2.